OData - API using SAP API hub in SAP S4 op

I've been studying recently BTP, I saw SAP API Hub There are many, many ready-made API, So I thought of using them in my own OP On , To achieve the purpose of using rapid development

stay SAP S4 OP Use in SAP API Hub Of API

First let's open up SAP API Hub - SAP API Business Hub(api.sap.com), Click on APIs

choice OData V2, Enter... In the right search box Purchase order( If you need anything else API Please modify )

Select first API Click on , stay Overview Interface selection EDMX download

stay S4 OP End SEGW Create a... In the transaction Project

Right click selection Import->Data Model from File

Choose the downloaded API file

Click on Finish, And then click Generate Generate

Generate the corresponding class

Next we ZCL_ZTAB_API_PO_PROCES_DPC_EXT double-click

Click on the way -> Inheritance method , choice A_PURCHASEORDER_GET_ENTITYSET redefinition

Then simply write a get PO Code of order information , Save activation

DATA lt_purchaseorder TYPE 
zcl_ztab_api_po_proces_mpc=>tt_a_purchaseorderitemtype.
  DATA ls_purchaseorder LIKE LINE OF lt_purchaseorder.

  SELECT a~ebeln,b~ebelp,b~werks,b~matnr,b~menge,b~meins
    FROM ekko AS a
    INNER JOIN ekpo AS b ON b~ebeln = a~ebeln
    INTO TABLE @DATA(lt_ekpo)
    UP TO 5 ROWS.
  IF sy-subrc EQ 0.
    LOOP AT lt_ekpo INTO DATA(ls_ekpo).
      ls_purchaseorder-purchaseorder = ls_ekpo-ebeln.
      ls_purchaseorder-purchaseorderitem = ls_ekpo-ebelp.
      ls_purchaseorder-material = ls_ekpo-matnr.
      ls_purchaseorder-plant = ls_ekpo-werks.
      ls_purchaseorder-purchaseorderitem = ls_ekpo-ebelp.
      ls_purchaseorder-orderquantity = ls_ekpo-menge.
      ls_purchaseorder-purchaseorderquantityunit = ls_ekpo-meins.
      APPEND ls_purchaseorder TO lt_purchaseorder.
      CLEAR ls_purchaseorder.
    ENDLOOP.
  ENDIF.

  CHECK lt_purchaseorder IS NOT INITIAL.

  et_entityset = lt_purchaseorder.  

Copy

To transaction code /n/iwfnd/maint_service, Click Add Service

We enter the system alias ( Because it was created OData The service is packaged locally , So the input LOCAL), And then do the screening , Choose services , Click add selected service

Select the package directly , Then make sure , Load service

Return to the service maintenance interface ： We can see that the service has been added to it

We can click SAP Gateway To test , Click on EntitySets, Select the method we just redefined Set

Click on the perform , We can see PO The data has been retrieved

The copy address opens in the browser , You can also view the returned Json